Improvement in iron safes



NITED STATES WM. ALFORD AND JOHN D. SPEAK,

IMPROVEMENT ATENT OFFICE.

OF DISTRICT OF'SOUTHWARK, PA.

IN IRON SAFES.

To all whom it may concern:

Be it known that we, WILLIAM ALFORD and JOHN D. SPEAR, of the district of Southwark, in the county of Philadelphia and State of Pennsylvania, have invented and discovered anew and useful Improvement in the Construction of Iron Chests or Safes, intended for the preservation of books, papers, and other valuables from combustion and we do hereby declare that the following is a fulland exact description of our improvement. I

We construct the chest or safe with which we intend to combine our improvement in the ordinary mode in which iron chests or safes intended to be fire-proof are made, viz: We make a double iron chest having a vacuum or empty space of from three to four inches between the'inner and outer chest. We also make the door double, having a vacuum of from three to four inches over the lock. The iron plate which forms the inside of the door, and the plate or plates which form the back part of the chest are constructed so as to be screwed on. No part of the construction above described is claimed by us as new. We then take pulverized chalk or whiting, which has been subjected to the action of acids, as hereinafter described, and has been partially deprived of its carbonic acid, the material which' we use being in fact the residual matter left from the manufacture of what is called mineral water after chalk or whiting has been subjected to the action of acids, for the purpose of expelling a portion of its carbonic acid, this residual matter consisting substantially of the substances named in the following analysis ofa specimen ofthe samebyDr. Charles T. Jackson, chemist:

Hygrometic water expelled at 212 Fahrenheit 5.34 Combined water expelled at red heat 1.32

Cabonate of lime i g acid Sulphate of lime, oxide of iron,

and silica 60.74 diff.

heat. We first pack the space on the inside of the door over the lock with this material so that the whole space is completely filled. We afterward screw on the plate or plates of iron, which form the inner side of the door. We then turn.

outer-chest may be filled with the material above described in a dry powdered state, in which case it may be packed with mallets; but we prefer to apply the material in the manner first mentioned.

The advantages of using the material above described arc,thatit is cheaper than any eq ually goodnon-conductin g substance, it beingthrown away as waste at the mineral-water establishments that it possesses a greater efficieucy to impede the transmission of heat than is possessed by any substances which have been used as non-conductors in the construction of safes, and that the safes constructed with this material as a non-conductor of heat may be subjected to an intense degree of heat without impairing its non-conducting qualities.

What we claim as our discovery, invention, and improvement, and desire to secure by Letters Patent, is-- I The application of chalk or whiting which has been subjected to the action of acids and has been partially deprived of its carbonic acid, the material which we use being in fact the waste or residual matter left from the manufacture of whatis called mineral water after chalk or whiting has been subjected 'to the action of acids, for the purpose of expelling a portion of its carbonic acid, this-residual matter consisting substantially of the substances named in the analysis before referred to in the construction of double iron chests or safes, in the manner above described, or in any other manner substantially the same.

WILLIAM ALFORD. JOHN D. SPEAK.

Witnesses:

Trrno. D. SPEAR, J OHN D. HARDEY, GEORGE Moonn. 

